The perimeter of rectangle ~$A$~ is 200 meters. The lengthof rectangle~$B$~  is 10 meters less than the length of rectangle ~$A$~ and the widthof rectangle~$B$~ is 10 meters more than the width of rectangle ~$A$~. If rectangle ~$B$~ is a square, what is the width, in meters, of rectangle ~$A$~?

10

20

40

50

60